1. Field of the Invention
The present invention relates to a motor driven camera in which film is wound and rewound by a motor.
2. Description of Related Art
In a conventional motor driven camera, a mechanism for feeding and stopping a frame of film is functionally independent from a mechanism for confirming or detecting a loading of a film, a terminal end of the film, a rewinding operation of the film, the completion of rewinding of the film or the like. The conventional camera mechanism has a rotor which rotates by one turn when a frame of film is fed, in association with a sprocket for feeding the film, regardless of the number of teeth of the sprocket. The film feeding mechanism further includes a one-turn switch which is made ON and OFF by the rotor to turn the motor ON and OFF. The one-turn switch also restricts the position of a picture plane with respect to the perforations of the film.
On the other hand, the mechanism for confirming or detecting the state of the film has a pulse generator which generates pulses in association with the rotation of the sprocket, so that the state of the film can be confirmed or detected by the pulse signals.
In particular, in a recent single-lens reflex camera, a spool drive is used in place of the sprocket drive mentioned above. In the spool drive, the film is fed by the sprocket when the film is loaded, but once the film is engaged onto the spool, the film is wound by the rotation of the spool. In the spool drive type, the sprocket always rotates when the film is loaded; that is, it rotates even when the film is not actually wound onto the spool. Therefore, it is impossible to detect a loading error by only detecting the rotation of the sprocket. This is the reason that a special mechanism for detecting such a loading error is indispensably provided in a conventional camera. For instance, the special detecting mechanism has a rotating member which continuously bears against the film to rotate in accordance with the movement of the film, so that the state of the film can be detected by rotation signals or rotation stop signals of the rotating member.
However, the inventor of the present invention has found that it is not necessary to provide a separate film feeding mechanism and film state detecting mechanism. The inventor's interest has been directed to the consolidation of the above-mentioned two mechanisms. To realize the consolidation, the inventor has conceived that the pulses which are generated in association with the feed of film should be functionally associated with the perforations of the film.